The present invention relates to detersive enzyme particles having a barrier layer and compositions employing the same. More particularly, the present invention relates to a protease enzyme particle for use in automatic dishwashing compositions.
The incorporation of detersive enzymes into automatic dishwashing detergents (ADD""s) is a relatively new concept. However, it has been determined that the use of detergent protease, amylase, etc., enzymes in dishwashing compositions provides improved cleaning performance on a variety of soils.
A recognized need in ADD compositions is to have present one or more ingredients which improve the removal of tough foods and stains (e.g., tea, coffee, cocoa, etc.) from consumer articles. Strong alkalis like sodium hydroxide, bleaches such as hypochlorite, builders such as phosphates and the like can help in varying degrees. Moreover, improved ADD""s make use of a source of hydrogen peroxide, optionally with a bleach activator such as TAED, as noted. In addition, enzymes such as commercial proteolytic and amylolytic enzymes can be used. The alpha-amnylase component provides at least some benefit with respect to the starchy soil removal properties of the ADD. ADD""s containing amylases typically can also deliver a somewhat more moderate wash pH in use, and can remove starchy soils while avoiding delivering large weight equivalents of sodium hydroxide on a per-gram-of-product basis.
It has been also discovered that protease enzymes are particularly effective for use in promoting the cleaning properties of ADD""s. However, the direct incorporation of the enzyme particles into a granular ADD composition can present problems. As noted earlier, many granular ADD formulations employ a source of hydrogen peroxide and an activator to produce an oxygen bleach system. Unfortunately, many enzyme components undergo oxidation when in contact with the components of an oxygen bleach system. Accordingly, during prolonged storage of the granular detergent ingredients, the enzyme ingredients undergo a degradation which reduces enzyme activity and overall performance of the detergent.
From the foregoing, it will be appreciated by those skilled in the art that the formulation of modern automatic dishwashing detergents is becoming increasingly complex. The need to separately manufacture, store, ship and formulate a wide variety of ingredients adds to the cost of such products. Therefore, it would be desirable to have the flexibility of formulation by the minimization of intimate contact of detergent ingredients thereby reducing some of the costs associated with the manufacture and handling of various ingredients.
Accordingly, the need remains for a granular enzyme particle which will protect the subject enzyme from oxidative degradation.
U.S. Pat. Nos. 4,381,247; 4,707,287; 4,965,012; 4,973,417; 5,093,021 and 5,254,287 all disclose enzyme particles for granular detergent compositions. U.S. Pat. Nos. 4,526,698; 5,078,895; 5,332,518; 5,340,496; 5,366,655; 5,462,804 and WO/95/02670 all disclose coated bleach particles.
This need is met by the present invention wherein a stabilized detersive enzyme particle for detergent compositions is provided. The enzyme particle of the present invention provides protection from oxidative degradation of the subject enzyme. The particle of the present invention employs a barrier layer on an enzyme-containing core layer. The barrier layer acts as a protective shield to the subject enzyme. If desired, additional stabilizing agents may also be added to the enzyme particle of the present invention.
Accordingly in a first embodiment of the present invention, an enzyme particle for a detersive enzyme is provided. The particle comprises a composite particle suitable for incorporation in a detergent composition comprising an enzyme-containing core material and a barrier layer coated on the enzyme-containing core material.
The preferred enzyme is a protease enzyme with the protease being derived from non-naturally-occurring carbonyl hydrolase variants having an amino acid sequence not found in nature, which is derived by replacement of a plurality of amino acid residues corresponding to position +76 in combination with one or more of the following residues +99, +101, +103, +104, +107, +123, +27, +105, +109, +126, +128, +135, +156, +166, +195, +197, +204, +206, +210, +216, +217, +218, +222, +260, +265, and/or +274 of a precursor carbonyl hydrolase with different amino acids, where the numbered position corresponds to naturally-occurring subtilisin from Bacillus amyloliquefaciens, being the most preferred and the naturally-occurring carbonyl hydrolase variants having an amino acid sequence not found in nature, which is derived by replacement of a plurality of amino acid residues corresponding to positions 76/103/104.
The enzyme core material may comprise a mixture of at least two different protease enzymes such as when at least one protease is a chymotrypsin-like protease enzyme and at least one protease is a trypsin-like protease enzyme. When employing the aforementioned mixture, the chymotrypsin-like protease enzyme is preferably a non-naturally-occurring carbonyl hydrolase variant having an amino acid sequence not found in nature, which is derived by replacement of a plurality of amino acid residues corresponding to position +76 in combination with one or more of the following residues +99, +101, +103, +104, +107, +123, +27, +105, +109, +126, +128, +135, +156, +166, +195, +197, +204, +206, +210, +216, +217, +218, +222, +260, +265, and/or +274 precursor carbonyl hydrolase with different amino acids, where the numbered position corresponds to naturally-occurring subtilisin from Bacillus amyloliquefaciens and the trypsin-like protease enzyme is a microbial alcaline proteinase.
In preferred instances, the composite particle further comprises an outer overlayer coated on the barrier layer, preferably a water-soluble polymer. Also, the enzyme containing core material may further include a bleach catalyst material or a stabilizing additive admixed in any or all of the layers, i.e. enzyme-containing core material, barrier layer and overlayer. Preferred stabilizing additives are selected from the group consisting of alkaline salts, antioxidants, chelants, radical quenchers, reducing agents and mixtures thereof with the reducing agents alkali metal sulfite, bisulfite or thiosulfate being the most preferred.
According to another embodiment of the present invention, an automatic dishwashing composition comprising, as a key component, from about 0.1% to about 20% by weight of the composition of the enzyme particle substantially as described above and from about 0.1% to about 99.9% by weight of the composition of adjunct automatic dishwashing detergent ingredients. The adjunct detergent ingredients are preferably selected from the group consisting of a source of peroxygen bleach, bleach catalysts, bleach activators, low-foaming nonionic surfactants, builders, pH-adjusting components, and mixtures thereof.
Accordingly, it is an object of the present invention to provide an enzyme particle which provides superior protection to the subject enzyme from oxidative degradation in a detergent composition. It is yet another object of the present invention to provide an enzyme particle having a barrier layer. It is still further an object of the present invention to provide an automatic dishwashing composition employing an enzyme particle having a barrier layer. These and other objects, features and advantages of the present invention will be readily apparent to one of ordinary skill in the art from the following description, drawings, and the appended claims.
All percentages, ratios and proportions herein are by weight, unless otherwise specified. Oxygen bleaches are, where noted, reported as xe2x80x9cAvOxe2x80x9d. All documents cited herein are, in relevant part, incorporated herein by reference.